     {:field (String. ^String name) ; copy the string. string/split is evil.
      :feature feature
      :valueType "category"
-     :scores vals}))
+     :rows vals}))
 
 (defmulti matrix-data
   "Return seq of scores, probes X samples"

     [{:field "name"
       :valueType "category"
       :feature probe-feature
       :scores probe-vals}
      {:field "position"
       :valueType "position"
       :rows (map #(select-keys % [:chrom :chromStart :chromEnd :strand]) columns)}

      {:field (String. ^String (first cols)) ; copy, because split is evil.
       :feature feature
       :valueType "float"
       :rows (mapv parseFloatNA (rest cols))}) ; eager
    (catch NumberFormatException e
      (data-line features cols "category"))))

